Process of making tubes from ingots



8.0KANO. I PROCESS OF MAKING TUBES FROM INGOT S- APPLICATION FILED DEC.24, I9I9.

1,413,694. I Patented Apr.- 25, 1922.

UNITE ATNT, oFFicE.

SOTARO OKANO, 0F HlEGASHI KU, OSAKA, JAPAN, ASSIGNOR TO NIHON' KOKWAN SHAFT KABUSHIKI KWAISHA, OF TOKYO, JABAN.

PROCESS OF MAKING TUBES FROM INGOTS.

Specification of Letters Patent. Patented Apr. 25, 1922.

Application filed December 24, 1919. Serial No. 347,229.

T0 (1 aria-0m it may concern:

Be it known that I. Serrano ()kAN'o, subject of Japan. residing at No. 2-} Kim Machi, .lligashi Ku, (.)saka,,Japan, have invented new-and useful Improvements in a Process of Making Tubesfrom Ingots, (for which 1 have filed an application in Japan December 21, 1918, Serial No. 43,033,) of which the following is a specification.

This invention relates to a process of making metal tubes directly from ingots and consists in making an axial slit through an ingot, and rolling the same between rolls until the thickness around the slit of the ingot is reduced to the thickness of the tube to be formed, or to a thickness a little greater, and when the ingot is passing from the last rolls, inserting into the. silt a mandrel firmly fixed in front of the ingot and making the tube by means of the said mandrel and a pair of grooved rolls between which the ingot is made to pass.

The object of this invention is to manufacture steel and other metallic tubes with comparatively smaller power and expense in a factory of a smaller scale than heretofore.

The accompanying drawings show my process, in which Fig. 1 is an ingot cut through at its central part. I I

Figs. 2 and 3 show the same as gradually reduced in thickness by rolls to the desired thickness.

Fig. 4 shows in plan view the ingots after being rolled to the proper thickness, and while bcing rolled out of the last rolls and being formed into a tube by a mandrel and a pair of grooved rollers;

Fig. 5 is vertical section of Fig. 4.

Fig. 6 is a plan view of the mandrel, and

Fig. 7 is a side view of the same.

'loexplain my invention in detail with reference to the accompanying drawings. (Z is an ingot, either cubic or oblong. with a slit 7) cut longitudinally through it, leaving on both sides of the slit spaces :r .1: equal to or a little greater than the thickness 1 of the tube to be made. Then the ingot is gradually reduced in thickness by passing it successively between rolls 0, d, until the hickness measuring from the slit, becomes eq al to, or a little greater than that of the tube to be manufactured.

\Vhen the ingot is passing from the last rolls, the edge of the mandrel f, which is securelyheld in front of-the ingot, is inserted in the slit 7) of the ingot. The mandrel, be'-' ing shaped with an edge I) like that of an ax but gradually rounded toward the rear part wall of the tube to be manufactured, and willbe rolled into the required tube from outside by the said rollers g g.

-According to the method as hitherto most commonly used, the ingot is first bored by forcing thereinto a mandrel and is then rolled into a required pipe. Thus it requires great power, and mechanical equipment, and consequently the expenses are very great. Besides, after boring a hole into the ingot, the work of rolling it out into a tube of'a required size is very difficult.

Now,. according to my invention, as the ingot having an axial slit cut through its central part and .reduced by passing it between a series of rolls to a thickness, when opened, corresponding to that of the pipe to be manufactured, is forced as it comes out of the last press against the mandrel, which acts like a wedge in opening the ingot'into a tube, "and at the same time the mandrel and a pair of grooved rollers fixed around the head of the mandrel, form the ingot into a tube, tubes of any desired size and thickness can easily be manufactured comparatively with small force, and simple equipment, and consequently with small expense- By the present process, tubes of substantially uniform wall thickness are produced, this being accomplished ,to a considerable,measure by the means which are used for opening out the slit ingots, this being done by the use of a mandrel f having a sharp edge or knife edge at the forward end which corresponds substantially with the length of the slit, and

having the surface of the mandrel taper from of my invention can be modified in plan Without departing from the spirit thereof.

I claim The process of manufacturing metal tubes direct from ingots having axial slits therethrough, which consists in rolling said ingots between pairs of rolls until each side of the ingot parallel with said slit is approximately equal in thickness to the wall of the tube to be formed, spreading the sides of the ingot, and supporting the interior of the tube at all points as it is being transformed from a flat blank to a cylindrical tube, and feeding the ingot While thus supported between a pair of semicircularly grooved rolls, whereby a tube having walls of uniform thickness is formed.

In testimony whereof I have signed my name to this specification in the presence of two subscribing Witnesses.

SOTARO oKANoL Witnesses W. E. AIBOROH, Y. HIRAIWA. 

